1. Field of the Invention
The present invention relates to a portable terminal apparatus such as a folding portable telephone apparatus.
2. Description of the Related Art
In portable telephone apparatuses (portable terminal apparatuses), a mouthpiece unit (a first body) has an attachment section (a first hinge arm) including an attachment hole (a first axis hole), inside of which a pair of engaging protrusions are provided at intervals of 180° along the entire length of the axis. Further, an axis-shaped case (a hinge axis) constituting a hinge has recessed grooves axially provided on an outer circumference thereof. The hinge is fitted to the attachment hole such that the recessed grooves are engaged with the engaging protrusions, allowing the mouthpiece unit (the first body) to be foldably attached to an earpiece unit (a second body) via the hinge (i.e., the case, the hinge axis). Related technology has been disclosed in, for example, Japanese Patent Application Laid-open No. 2004-84805.
In the related-art portable terminal apparatus, the engaging protrusions in the attachment hole (the first axis hole) are formed up to end faces of the attachment section (the first hinge arm). This structure has a problem that, when strong force such as twisting force acts between the mouthpiece unit (the first body) and the earpiece unit (the second body), the force is concentrated on bases of the engaging protrusions at the end faces of the attachment section (the first hinge arm), causing cracking in the bases and thus easily breaking the attachment section (the first hinge arm). This problem is significant in apparatuses in which large stress is applied to the attachment section (the first hinge arm), for example, in portable telephone apparatuses used to view a television image by rotating a liquid crystal display (the second body) thereof sideways.